In an automotive vehicle, a seatbelt buckle is generally fixed in a length in relation to a vehicles seat. The fixed length seatbelt buckle can be coupled to a vehicle floor, or be coupled to a vehicle seat track such that the fixed length seatbelt buckle can move between fore and aft positions with the vehicle seat. Vehicle seats have evolved to include many different forms of seat position adjustments. Currently, vehicle seats are adapted to not only adjust in the fore and aft positions, but are further adapted to tilt, as well as raise and lower the seat pan to accommodate the needs of a vehicle user. With a fixed length seatbelt buckle assembly in place, the user has poor accessibility to the seatbelt buckle assembly when the vehicle seat is in a full up position. This is because the fixed length seatbelt buckle assembly, as coupled to a vehicle seat track or a vehicle floor, does not adjust in length in accordance with the vehicle seat position. Thus, while the seatbelt buckle may be readily accessible when the seat cushion is in a full down position, the same is not true when the vehicle seat cushion is in a full up position. The poor accessibility is particularly noticeable for smaller and older vehicle occupants, because they are more likely to adjust the seat height to near full up position.
Known telescoping buckle presenters use a variation of buckle pretensioner hardware which is modified to be driven by a dedicated motor to change the buckle length. This change in buckle length (or height) occurs independent of the vehicle seat adjustment typically with separate dedicated controller circuits and switches. This system “presents” (lengthens) the buckle beyond normally available length to make it accessible for easy buckling when an occupant first enters the vehicle. Then after the occupant buckles the seatbelt, the “presenter” shortens the buckle to a normal length. This system is significantly larger and heavier than conventional buckles, making it challenging to package in tight space between the seat and center floor console. It also bears significant cost due to the additional motor, electronics, control logic and switches. Thus, such a dedicated system requires complex control logic to determine when to extend and when to retract the buckle length for optimum crash performance.
Other buckle presenters are self adjusting using mechanical means such as a rack and pinion mechanism or other systems using a rigid or flexible strap mounted seatbelt buckle attached to a lower slider mechanism. An upper portion of the buckle is coupled mechanically to the seat pan. This self adjusting buckle presenter does not require any electrical controls or logic, but does require a mechanical “clutch” type mechanism to allow the buckle length adjustment with seat height adjustment, yet lock the buckle length adjustment when it is under load, such as in a collision event. In this system, the buckle length range is limited by the seat pan height adjustment, since it is directly attached to the seat pan for vertical travel therewith. This reinforcement of seat structure adds significant weight and cost to the seat assembly, thereby calling for a larger package than the typical static buckle it replaces.
Referring to FIG. 1, a fixed length seatbelt buckle 1 of the prior art is shown as coupled to a vehicle seat 2. Many common seat structures include a fixed length seatbelt buckle 1 having an anchorage 3 which is coupled to an upper track of the seat assembly 2. In this way, the fixed length seatbelt buckle 1 moves to fore and aft positions in a direction as indicated by arrow A as the position of the seat assembly 2 is adjusted. Further, referring to FIG. 2, the seat assembly 2 is adjustable vertically between a full up position B, as shown in FIG. 2, and a full down position C as indicated in FIG. 1. The seat assembly 2 moves between the full up position B and the full down position C in a direction as indicated by arrow D shown in FIG. 2. The ability of the vehicle seat 2 to move between positions B and C results in a minimal portion of the seatbelt buckle 1 being accessible when the seat height is in the full up position B as shown in FIG. 2. Accordingly, when the vehicle seat 2 is in the full down position C, the fixed length seatbelt assembly 1 is more accessible. In the configuration as shown in FIG. 2, the fixed length seatbelt is not only less accessible as compared to FIG. 1, but the position of the buckle 1 also degrades the overall comfort for the vehicle occupant when attempting to engage the seatbelt buckle 1.
Thus, there is a desire to provide a telescoping seatbelt buckle assembly that will adjust the seatbelt buckle length in accordance with the position of the vehicle seat, such that a relative position of the buckle to the seat is maintained in a full range of motion of a vehicle seat including, but not limited to, fore and aft positions, tilted positions, as well as raised and lowered seat positions.